Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantas nacionalidades estão listadas para o jogador Glen Irwin?
 ###Tabelas: CREATE TABLE handicap_results_top_10 (handicap_results_top_10_id AUTO_INCREMENT PRIMARY KEY, Position INT, Sail number VARCHAR, Yacht VARCHAR, State/country VARCHAR, Yacht type VARCHAR, LOA (Metres) VARCHAR, Skipper VARCHAR, Corrected time d:hh:mm:ss VARCHAR) CREATE TABLE quarterfinal_3 (quarterfinal_3_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Athlete VARCHAR, Country VARCHAR, Time VARCHAR, Notes VARCHAR) CREATE TABLE wins_3 (wins_3_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Date INT, Championship VARCHAR, Surface VARCHAR, Opponent in the final VARCHAR, Score in the final VARCHAR) CREATE TABLE winning_head_of_the_river_championship_events (winning_head_of_the_river_championship_events_id AUTO_INCREMENT PRIMARY KEY, Crew INT, Open 1st VIII VARCHAR, Open 2nd VIII VARCHAR, Open 3rd VIII VARCHAR, U16 1st VIII VARCHAR, U16 2nd VIII VARCHAR, U16 3rd VIII VARCHAR, U15 1st IV VARCHAR, U15 2nd IV VARCHAR, U15 3rd IV VARCHAR, U15 4th IV VARCHAR, U15 5th IV VARCHAR, U15 6th IV VARCHAR) CREATE TABLE round_three (round_three_id AUTO_INCREMENT PRIMARY KEY, Pick # INT, Player VARCHAR, Position VARCHAR, Nationality VARCHAR, NHL team VARCHAR, College/junior/club team VARCHAR)  
SELECT COUNT Nationality FROM round_three WHERE Player = Glen Irwin